beneath the table to the abstract. Use the Word Count cmd under Utilites menu for counting Significance The prevention of tuberculosis in colonies on nonhuman primates is essential to the maintenance of the integrity of primates used in biomedical research. Such prevention efforts rely heavily on the use of the tuberculin skin test (TST) for screening and surveillance. The periodic unavailability of Mammalian Old Tuberculin (MOT) has increased the urgency for developing alternative strategies for TB testing in nonhuman primates. Objectives To evaluate a variety of alternative TB screening and diagnostic approaches to complement or replace the TST for use in nonhuman primates. Alternative strategies being evaluated include molecular biology approaches including direct and indirect detection of TB by polymerase chain reaction (PCR), and in vitro cellular assays. Results Blood and tissue samples have been collected from TST reactors and TB culture positive macaques for use in development and validation of these alternative diagnostic and screening assays. To date, we have demonstrated the ability of a "hybrid" INF-gamma ELISA (utilizing components of 2 commercially available products) to differentiate between Avian and Mammalian TST reactions. Future Directions Biological samples will continue to be collected from TST positive macaques as they are identified. Through collaboration with Tulane Regional Primate Research Center, we will have access to samples from rhesus macaques experimentally infected with M. tuberculosis. Additional experimental studies involving immunization of macaques with Complete Freunds Adjuvant and BCG will be performed to provide additional reagent samples for test evaluation and validation. KEY WORDS tuberculosis, screening, macaques, methods FUNDING NIH Grant RR00169